Same‐Sex Marriage Legalization and Sexually Transmitted Infections Across Europe

I examine how same‐sex marriage laws affect sexually transmitted infection (STI) rates, using country‐level panel data from Europe. Dynamic difference‐in‐differences models show that same‐sex marriage laws decrease the spread of shorter‐term (syphilis, gonorrhoea) and longer‐term infections (HIV, AIDS) among the general population. These effects are persistent over time and are much stronger than other same‐sex relationship recognition policies. Further investigation reveals significant heterogeneity; same‐sex marriage laws lead to sizeable decreases in all STIs among the most at‐risk population for an infection, men who have sex with men, with additional positive externalities on the health capital of heterosexual men and women.